Fungal Skin Infections Practice Questions

Q: A patient with bronchial asthma on long -term inhaled corticosteroid therapy presents with whitish plaques over the palate and tonsillar region. What is the most likely diagnosis?

Oral candidiasis. ***Oral candidiasis*** - Inhaled corticosteroids suppress local oral immunity, predisposing patients to opportunistic **Candida albicans** infection, characterized by **creamy white plaques** that can be scraped off. - The palate and tonsillar region are classic sites for this infection in patients using **metered-dose inhalers (MDI)** without proper oral rinsing techniques. *Oral lichen planus* - Typically presents as **lace-like white lines** (Wickham striae) on the buccal mucosa, rather than wipeable plaques. - It is a **chronic inflammatory condition** often characterized by T-cell mediated autoimmune destruction of basal keratinocytes, not an infectious process. *Aphthous ulcer* - Presents as painful, **shallow ulcerations** with necrotic centers and erythematous halos, not as white plaques. - These are **recurrent ulcers** typically found on non-keratinized mucosa and are associated with stress, trauma, or nutritional deficiencies. *Leukoplakia* - Presents as **white patches** or plaques on the oral mucosa that **cannot be rubbed off**. - It is a **potentially premalignant lesion** associated with chronic irritation like tobacco or alcohol use, unlike the reversible fungal infection seen here.

Q: A patient from TN, presents with a long -standing painless swelling of the foot with multiple discharging sinuses, as shown in the image. HYPHAE in biopsy. What is the most appropriate treatment?

Long -term antifungal therapy with surgical debridement. ***Long-term antifungal therapy with surgical debridement*** - This patient presents with features of **eumycetoma** (a fungal form of mycetoma), characterized by painless swelling, sinus tracts, and the presence of **hyphae** on biopsy. - Because fungal infections in mycetoma can be deep-seated and difficult to clear, the standard of care involves a combined approach of **prolonged antifungal therapy** (such as itraconazole or voriconazole) alongside **surgical debridement** of necrotic tissue. *Immediate amputation* - Amputation is reserved for cases with severe, extensive tissue destruction, secondary infection, or loss of function, rather than an initial management step. - Most cases of mycetoma can be managed conservatively with medical and surgical interventions before considering aggressive measures like amputation. *Short-term antifungal therapy alone* - **Eumycetoma** is a chronic, slow-growing infection that requires very long courses of antifungal therapy, often lasting for months or even years. - Short-term treatment is ineffective and will result in high **relapse rates** given the deep, granulomatous nature of the fungal infection. *Surgical debridement only* - Surgical debridement alone is insufficient as the fungal elements often infiltrate deep into the subcutaneous tissue and bone, leading to high rates of **local recurrence**. - Medical therapy is essential to treat the residual fungus that surgery alone cannot clear, necessitating the **combined therapeutic approach**.

Q: A patient presents with lesions on the axilla, groin, and trunk. The lesions are characterized by central clearing and a surrounding papulovesicular margin that progressively increases at the borders. Which of the following investigations would be preferred?

10% KOH mount. **Explanation:** The clinical presentation described—lesions with **central clearing** and an **active papulovesicular margin** spreading centrifugally—is the classic hallmark of **Tinea Corporis** (Dermatophytosis). **Why 10% KOH mount is the correct answer:** The 10% Potassium Hydroxide (KOH) mount is the **gold standard bedside investigation** for diagnosing fungal skin infections. KOH acts as a keratolytic agent, dissolving keratinocytes and debris, which allows for the clear visualization of fungal elements under a light microscope. In dermatophytosis, one typically observes **branching, septate hyaline hyphae**. **Analysis of Incorrect Options:** * **A. Wood’s lamp examination:** While useful for Tinea Capitis (e.g., *Microsporum* species) or Erythrasma (coral-red fluorescence), most species causing Tinea Corporis (like *T. rubrum*) do not fluoresce. * **C. Skin biopsy:** This is an invasive procedure generally reserved for atypical presentations or deep fungal infections. It is not the first-line investigation for superficial dermatophytosis. * **D. Patch testing:** This is the investigation of choice for **Allergic Contact Dermatitis**, not fungal infections. **High-Yield Clinical Pearls for NEET-PG:** * **Tinea Incognito:** This occurs when a fungal infection is treated with topical steroids, leading to a loss of the classic annular morphology and making diagnosis difficult. * **Culture Medium:** If KOH is inconclusive but suspicion is high, the gold standard culture medium is **Sabouraud’s Dextrose Agar (SDA)**. * **Erythrasma vs. Tinea:** Erythrasma (caused by *Corynebacterium minutissimum*) lacks the active border and central clearing seen in Tinea and shows coral-red fluorescence under Wood's lamp.

Q: Scutula is classically seen in which of the following conditions?

Favus. **Explanation:** **Favus** (Option A) is a chronic inflammatory form of Tinea Capitis, most commonly caused by the anthropophilic fungus *Trichophyton schoenleinii*. The hallmark clinical feature of Favus is the **Scutulum**. A scutulum is a yellowish, cup-shaped crust composed of dense masses of fungal mycelia, epithelial debris, and inflammatory cells. These crusts often have a characteristic "mousy odor" and, if left untreated, lead to extensive scarring (cicatricial) alopecia. **Analysis of Incorrect Options:** * **Small spore ectothrix (Option B):** Characterized by fungal spores forming a sheath around the hair shaft. It typically presents as "Gray Patch" tinea capitis with brittle, broken hairs, but does not form scutula. * **Endothrix (Option C):** Spores are found inside the hair shaft (e.g., *T. violaceum*). This leads to the "Black Dot" appearance due to hair breaking at the level of the scalp. * **Kerion (Option D):** An exaggerated inflammatory host response to zoophilic fungi (e.g., *T. verrucosum*). It presents as a painful, boggy, inflammatory mass with pustules and sinus tracts, rather than the dry, cup-shaped crusts of Favus. **High-Yield Clinical Pearls for NEET-PG:** * **Favus Triad:** Scutula, mousy odor, and cicatricial alopecia. * **Wood’s Lamp:** Favus (*T. schoenleinii*) shows a characteristic **dull green** fluorescence. * **Microscopy:** On KOH mount, Favus shows **"Godet" or "Favic chandeliers"** (antler-like branching hyphae) and air bubbles within the hair shaft. * **Treatment:** Oral Griseofulvin remains the traditional gold standard, though Terbinafine is frequently used.

Q: A 24-year-old man presents with multiple small hypopigmented macules around hair follicles on the upper chest and back. Scratching of the lesions with a glass slide reveals fine scaling. What is the investigation of choice for diagnosing this condition?

KOH preparation of scales. ### Explanation The clinical presentation of small hypopigmented macules around hair follicles with fine scaling (evoked by scratching, known as **Besnier’s sign** or the "coup d'ongle" sign) is classic for **Pityriasis versicolor** (Tinea versicolor), caused by the yeast *Malassezia furfur*. **1. Why Option A is Correct:** The investigation of choice for any superficial fungal infection is a **KOH (Potassium Hydroxide) preparation**. When scales from Pityriasis versicolor are treated with 10% KOH, microscopy reveals a characteristic **"Spaghetti and Meatballs" appearance** (or "Banana and Curd" appearance). This represents a mixture of short, thick fungal hyphae and clusters of round yeast cells. **2. Why Other Options are Incorrect:** * **Option B (Tzank test):** Used for diagnosing viral infections (e.g., Herpes Simplex, Varicella) by identifying multinucleated giant cells. * **Option C (Slit Skin Smear):** Primarily used for diagnosing Leprosy (to look for Acid Fast Bacilli) and Leishmaniasis. * **Option D (Skin biopsy):** While it would show fungal elements in the stratum corneum, it is an invasive procedure and unnecessary for a superficial infection that can be diagnosed bedside. **3. High-Yield Clinical Pearls for NEET-PG:** * **Wood’s Lamp Examination:** Lesions show a characteristic **Golden Yellow fluorescence**. * **Culture:** *Malassezia* is lipophilic; it requires the addition of **olive oil** to the culture medium (e.g., Dixon’s agar) for growth. * **Treatment:** Topical antifungals (Ketoconazole shampoo, Selenium sulfide) are first-line. Oral Fluconazole or Itraconazole is used for extensive cases. * **Besnier’s Sign:** The accentuation of fine scales upon scratching the lesion is a pathognomonic clinical sign.

Question 1

A patient with bronchial asthma on long -term inhaled corticosteroid therapy presents with whitish plaques over the palate and tonsillar region. What is the most likely diagnosis?

Accepted Answer

Oral candidiasis

Answer

Oral lichen planus

Answer

Aphthous ulcer

Answer

Leukoplakia

Question 2

A patient from TN, presents with a long -standing painless swelling of the foot with multiple discharging sinuses, as shown in the image. HYPHAE in biopsy. What is the most appropriate treatment?

Accepted Answer

Long -term antifungal therapy with surgical debridement

Answer

Immediate amputation

Answer

Short-term antifungal therapy alone

Answer

Surgical debridement only

Question 3

A patient presents with lesions on the axilla, groin, and trunk. The lesions are characterized by central clearing and a surrounding papulovesicular margin that progressively increases at the borders. Which of the following investigations would be preferred?

Accepted Answer

10% KOH mount

Answer

Wood's lamp examination

Answer

Skin biopsy

Answer

Patch testing

Question 4

Scutula is classically seen in which of the following conditions?

Accepted Answer

Favus

Answer

Small spore ectothrix

Answer

Endothrix

Answer

Kerion

Question 5

A 24-year-old man presents with multiple small hypopigmented macules around hair follicles on the upper chest and back. Scratching of the lesions with a glass slide reveals fine scaling. What is the investigation of choice for diagnosing this condition?

Accepted Answer

KOH preparation of scales

Answer

Tzank test

Answer

Slit Skin Smear Examination

Answer

Skin biopsy of lesion

Fungal Skin Infections — MCQs

Fungal Skin Infections — MCQs

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